10 steps to more energy-efficient buildings

The U.S. is awash in commercial building space—enough to account for 18% of the country’s energy consumption, including 36% of electricity usage. And much of that energy is wasted. Efficiency experts say it’s possible to slash energy use in many buildings with relatively simple—and often inexpensive— measures. Here are their top recommendations:

1. Change the Culture

Take inventory of your office space. How many employees have space heaters at their desks? Minifridges? Christmas lights still blinking away? It’s time to get ruthless. First, create an inviting area for shared microwaves, coffee makers and combination printer-fax-copiers. Then ban cubicle energy hogs and challenge employees to change their culture. Everyone should make a point of turning off lights, shutting down unused appliances and wearing a sweater in lieu of using a heater. Try efficiency contests among departments (with prizes!) to spark interest.

2. Shut ‘Em Down

Consider installing a system on your computer network that will put individual desktops into sleep mode when they’re not being used. Or timers that shut down workers’ computers 15 minutes after the scheduled end of their shift. (Those working late can override the shutdown with a click of the mouse.) Same thing with appliances and lights: Set them to shut off after everyone has gone home. This can cut utility costs 4% or more.

3. See the Light

Simply swapping out incandescent bulbs for more-efficient compact fluorescents or LEDs can help a great deal. For more impact, look at corridor lighting. In a recent renovation for a Denver law firm, Don Fitzmartin, a project manager focused on energy-efficient retrofits, increased the distance between hallway fixtures to 16 feet from 12 feet and had the walls repainted a lighter color so the space still looked bright. That cut energy use in the 110,000-square-foot renovated space by 5% at a fairly low cost, he says.

4. Go Retro

Commission an audit of the heating, air-conditioning and other building systems to compare their performance with design specifications. That may identify simple fixes—cleaning filters, replacing a leaky valve—that can significantly improve efficiency. It may be possible to shave energy use 4% to 6% through such techniques, known as retrocommissioning.

As part of an effort to convince more New Yorkers to install solar panels on rooftops, the City University of New York has created a color coded digital map of the city that identifies which buildings and roofs get the most sunlight.

5. Let the Sun Shine

Willing to spend a bit more? Consider daylighting. Several companies sell rooftop devices that capture sunlight and distribute it more effectively than a skylight. Daylighting can eliminate the need for overhead lighting, at least on sunny days, cutting energy use by 10% to 15%.

6. Spruce Up the Space Plan

If you’re planning a cosmetic renovation, take the opportunity to make some energy-saving changes, too. Try lowering cubicle walls to facilitate the flow of air and sunlight. Eliminate some overhead fixtures, especially those near sunny windows, or at least install daylight sensors that automatically dim the lights when they’re not needed. If employees need stronger task lighting, give them LED desk lamps.

7. Loosen Up

It takes loads of energy to maintain a constant temperature. Replace existing thermostats with models that allow "dead bands." Setting a dead band of 69 to 75 degrees means the heating, ventilating and AC system won’t kick in unless the building temperature drops below 69 or rises above 75. This step can pare costs 3% or more.

8. Control Your Fans

In many heating and air-conditioning units, the fans have just two settings: off or full speed. Installing variable-speed fans can yield big gains in efficiency. Another tip: If there are multiple units for one floor, make sure they can operate independently, so only the space being used on any given day is heated or cooled. When Mr. Fitzmartin took these steps in the law firm he renovated in Denver, he cut electricity usage by 9%.

9. Upgrade the Envelope

Upgrades to the building envelope are the most expensive. Windows are an obvious place to start. And roofs painted in light, reflective colors don’t absorb solar heat, thus keeping buildings cooler during the summer.

10. Head Back to the Future

Many older buildings were designed to be comfortable without central air conditioning, but over time, windows, skylights and door transoms were sealed up and the buildings ceased to breathe. Consider reactivating the power of passive heating and cooling by making those openings operational again.